Front wheel hub assembly design
1 — Hub
2 - Polyurethane sealing ring
3 - Tapered roller bearing
1. Remove the hub (1) (see Section Removal and installation front wheel hubs).
2. Remove the tapered roller bearing (3) from the hub journal.
3. Remove the polyurethane sealing ring (2) - must be replaced.
4. Installation is carried out in the reverse order, do not forget to lubricate the NEW polyurethane ring (2) and bearing (3) before installation. Also fill the cavity in the hinge housing between the tapered roller bearings with about 80 grams of universal grease.
(Material borrowed from an online resource: MercedesMan)